Reversible planetary piston pump



REVERSIBLE PLANETARY PISTON PUMP Filed Dec. 19', 1,936

"l /6 il 2 Sheets- Shea 1N VEMTOIQ ',US'CLV Rudolf Lind berg *1I* 28,i937. G, R LLNDBERG 193,474

REVERSIBLE PLANETARY PSTON PUMP Filed Dec, 19, 195e 2 lshets-sheet 2 Z/0 r,72 \,C

@151m Rudolf Lindberg \NVENTOR Patented Dec. 2s, 1937 gleam PATENTOFFICE REVERSIBLE 4PLANETAIY PISTON PUMP l Gustav Rudolf Lindberg,Overum, Sweden Application December 19, 1936, serial No. 116,669

, In Denmark February 11, 1936 '1 claims. (01. 10a-431) The presentinvention relates to an arrangement in a reversible planetary Pistonpump of the kind, whose pump casing has two Ypump* cylin-V ders, whichare connected with each other and ings are provided, and inwhich pumpthe'impeller consists of two pump pistons, each provided in itscylinder, and an intermediate member radiallyY connecting theA saidcylinders, the

lV said impeller being adapted to bc actuated byV driving and guidingmeans' soV constructed that an eccentric motion can be imparted to'eithepiston, so that they are caused to move synchro` nously with each other.Y

15 One object of the invention is, in a driving means, in which only oneof the pistons is actuated to accentric motion'on a shaft in itscylinder, to so shape the guiding means that an exactly correspondingeccentric motion is imparted to theother piston. Preferably the guidingmeans consists of a roller or cylindrical shaft extending throughslots'in the connecting portion and rotatably mounted in the casing.

A further object of the invention is to provide 25 means of such a kindthat an absolutely effective Y tightening is eifected bothV betweenpistons and the walls of the workingcylinders and between the saidcylinders and the suction'and delivery side after each strokeof thepistons, and thatin 51 the last mentioned positions cushioning meansarise in connection with the sealing means so as to obtain a smooth andquiet run of the impellersrduring the strokes., 'V VThe pumping devicemay just as advanta- 3,3: geously be use dY as a machine, a water motoror Y The Vaccompanying drawings illustate, way

of example, a constructional form ofV the'invention.

,0- Figure; 1 shows a section perpem'iicularlyv toV with only half thepump and showing a detail 5o Von a modifiedV scale.

`Figure 6 shows a modied detail.

The pump casing comprises two cylinders I, 2V

located side by side, somewhatspaced with respect to one another andconnected with'each r 55 other by means of an intermediate portion, in

between which the suction and delivery ope11.

which suction and delivery openings 3, 4 are provided right opposite toeach other about perpendicularly to the driving shaft. If desired, theducts `opening into the suction and delivery openings may be arrangedparallel with the driving 5 shaft, as indicated in dashed'circularlines, atzl and 8, in Figure 1. In a constructional form of the saidkind the outer ends ofthe openings 3, 4 are shut off, so that a suctionand pressure cham-V ber, respectively, is formed in the pump casingproper. The pump casing is provided with one stationary and oneremovable cover 5 and 6, respectively. 1 Y Y The impeller consistsof'two pistons Sand HL, one in each cylinder and an intermediate meml5ber II, rigidly connecting said pistons. The said member, with concaveside faces merges with the cylindrical faces o-f the pistons. Thepistons 9, Ill are coated with a coating I2 of yielding or elasticmaterial, for example, a soft metal alloy, caoutchouc or the like, so asto facilitateV smooth sliding of the. pistons on the cylinder walls andto provide for an elective sealing elect Vagainst the walls, also inaxial direction. Moreover, the pump pistons and the cylinder walls bythis arrangement need not be made with the precision required in casemetallic surfaces are to cooperatewith each other. Preferably, also theintermediate memberV II is provided with such a coating I2', integralwith the coating I2, so that 30 the coating may be applied to theimpeller Without joints. These coatings, however, may ,b e dispensedwith, without the purpose of the invention beingabandoned, or they may be varied in such a `manner that a coating I2" is applied to the 35cylinder walls, instead of being applied to the* pistons, as shown inFigure 5.

`Adriving shaft I3,extendsconcentrically into the pumpV cylinder I andon the same there is provided a cam I4 to Vdrive the piston 9 around.'40 Said cam is so shaped that at the driving the center of the pistonmoves along acircular path I5 and itsperiphery rolls on the cylinderwall. In Vthe member II there is provided a slot I9 and in thecovers 5,6 slots I8. A cylindrical shaft or 45 roller I'I extends through theslot I9 and is loosely or rollably mounted in the slots I8. The slotshave av largerextension in the plane 'through the piston axes and thelongitudinal direction of the casing covers', respectively, than theshaft il'. 50 Thus, the extension of the slots I8 is'about equal to thesum of the shaft diameter and theradius Vof-the Vcircle about which theshaft center of the pistonsoscillates, the central line ofthe saidslotsV I8 coinciding with the transversal plane through 55 the center ofthe pump casing. Thus, during the pumping work, in addition to a rollingmotion, also an up-and-down motion in the slots I8 may be imparted tothe shaft I'I, the connecting member II being swingable and displaceablerelatively to the shaft.

The shaft I'I has an annular groove 20, so that liquid, which may enterthe slot I9 is able to circulate in the same without resistance, andmoreover the ends of the shaft may have convex shape, as shown in Figure2, in order to admit of such circulation also in the slots I8. The slotmay be replaced by holes or ducts. The walls of the slot I9 and, ifdesired, also those of the slots I8 are provided with a coating and aguiding surface, made of some material resistant to wear and tear, asindicated at 3D.

At the limiting edges of the suction and delivery openings there areprovided groove-shaped axial recesses 22 in the cylinder walls. On theimpeller about at the place where the concave surfaces of the connectingmember I I merge with the cylindrical surfaces of the pistons 9, I0there are provided rounded axial sealing edges 23 of a shapecorresponding approximately to the shape of the recesses 22 and, for thepurpose of sealing oif the respective cylinder chamber, cooperating withthe same in certain positions of the impeller.

In the piston 9 spring-acting roller or antifriction bearings may beprovided between the cam VI4 and the bearing surface of the piston,marked by a dash-and-dot line 32 (Figure 6), in order to obtain ayielding motion between the elements. Or also, a play may be providedbetween the shaft I3 and the cam, indicated at 33, by which also acertain spring-action can be obtained between said elements. 34indicates a preferably square key, which may be used in this case forconnecting the members I3 and I4 with each other and locatedsubstantially opposite said play.

The operation is as follows. In the position shown in Figure l the upperpump piston 9 has accomplished one stroke. The sealing edges 23 extendinto the recesses 22 and block the cylinder chamber a from the suctionand delivery openings, so that the liquid sucked into the chamber duringan earlier stage of the stroke is kept enclosed there. The lower pumppiston I0 with its outer end rests against the cylinder wall and, in afluid-tight manner, blocks the two chambers b and c, from each other, i.e. the delivery side from the suction side. During this movement liquidpresent in the chamber b is expelled in the direction of the arrow inFigure 1 and sucking-in is effected in the chamber c, as is also clearfrom the drawn arrows. When the shaft I3 continues to move in thedirection of the arrow the piston 9 is swung to the left, the piston I0to the right, and the periphery of the piston 9 is caused to contactwith the cylinder wall, the sealing engagement, at 22, being released.The liquid in the chamber a is pressed out through the opening 4, thevolume of the chamber being successively reduced according as therolling motion of the piston 9 on the cylinder wall continues. When theshaft has turned half a turn the piston 9 has the same position as thepiston Ill of Figure l. The liquid in the right part of the chamber a isstill being pressed out, vacuum arising in the left part, so thatsucking of liquid takes place. The more the piston 9 continues to theposition shown in the figure the more the volume of the chamber a isincreased and the more liquid is sucked until the shaft has rotated awhole turn, when the chamber is again completely blocked.

On account of the shapes of the guiding shaft I1 and of the slots thepiston I0 will, of course, move in the indicated direction of the arrow,i. e. synchronously with and in a direction opposite to that of thepiston 9 with its center of axis along the circle I6. Thus, if thepiston I0 is moved in the direction of the arrow its surface rollsagainst the cylinder wall under permanent sealing between the suctionand delivery side, during which the volume of the chamber c increasesmore and more at the cost of the chamber b. When the driving shaft hasrotated half a turn from the shown position the piston Ill has reached aposition which corresponds to that of the piston 9 in the drawings andseals the common chamber b, c from the suction and delivery openings.

As is seen from arrows marking the directions of flow the medium passesspirally through the pump.

When the piston I0 is moved towards and away from the position shown inFigure 1, the angular speed of the piston I0 is increased on account ofthe displacement of the shaft Il' upwards in the slots I8, so that thevolume of the chamber b decreases more rapidly than the volume of thechamber a., by which the total outflow can be kept practicallycontinuous. The reverse course of motion will take place when the pistonIU with its center moves within the upper half of the circle I6.

The depth of the recesses 22 is preferably made somewhat larger than theheight of the sealing edges 23, so that chambers or cavities 3l areobtained (Figure 4). During the pumping movements the liquid remainingin the said cavities will act as liquid cushioning means, so that whenthe sealing edges 23 enter the recesses 22 a noiseless and quiet workingwithout shocks and blows is obtained also in case of considerablesuction heads.

The two cooperating portions 2l and 23 may be arranged in a contrarymanner, as shown in Figure 5, recesses 22' thus being provided on thepistons and sealing edges 23 on the cylinder walls.

On account of the shown concave shape of the connecting member a smoothtransition is obtained between the suction and delivery openings and thepump chambers. Therefore, the pumped out liquid moves through the pumpin an even flow and on account of the double-acting constructionYsubstantially in a continuous flow without eddies being formed, whichis of a special importance when pumping, for example, a liquid such asmilk or the like, which, in case of eddes, easily may be subjected toseparation. The efciency is kept high thereby that the pump need neverwork with unreliable sealing between the suction and delivery sides.

The removable cover 6 is carried by bolts 25, which extend through thecasing (see Fig. 1) and are provided with heads indicated by 24. Theoperating member 26 is provided with a screw 21, which extends throughthe hub 28 of the stirrup member 29. The point of the screw is guided ina recess in the cover 6. The ends of the arms of the stirrup member 29are arranged as fastening members (claws or the like) which engage thebody 25 of the respective bolts. When the cover 6 is to be removed fromthe position shown in Figure 3 the operating member is turned in such amanner that there is no pressure on the stirrup member, after which thelatter is turned in anti-clockwise direction, until it has beencompletely liberated andV the 'cover can be removed so that the interiorparts of the pump will be easily accessible for inspection, cleaning andrepairing, if any.

Having now described my invention, `what I claim as new and desire tosecure by Letters Patent ist. Y

l. In a reversible planetary piston pump, a Vcasing comprising twocylinders arranged side by side and having openings in their adjacentsides communicating with one another; inlet and outlet openingscommunicating with said cylinder openings at opposite sides, an impellerin said casing, said impeller comprising two rotary pistons, arrangedone in each cylinder, and a rigid connecting member between said pistonsYconstituting a partition between the inletV and outlet openings, asingle eccentric drive operatively en gaging the piston of one of thecylindersand imparting a rotary oscillation to said piston, andguidingrmean's -for said connecting member for causing the piston in theother cylinder to move synchronouslyjwith the piston in the rstcylinder, said guiding means consisting of a shaft eX- tending through aslot of the connecting member and being movably mounted in slots of theWalls of the pump casing, the slot of the connecting member and theslots inthe walls of the pump casing having a larger extension intheplane through the piston axes then said movable shaft, the latterreceiving simultaneously a rolling motion relatively to its own axis anda longitudinal movement relatively to the slots in the Walls of the pumpcasing.

2. A reversible planetary pistOn pump as claimed in claim l, in whichthe connecting mem-V ber merges with substantially concave sides intothe cylindrical faces of the pistons. Y

3. A reversible planetary piston pump asV claimed in Yclaim l, in whichsaid shaft has a recess and convex axial endl faces, the said recess andfaces being so arranged as to make possible circulation Vof liquid,which may have entered all said slots.

4. A reversible planetary piston pump as claimed in claim l, in whichthe slot of the connecting member and the slots of the walls of the pumpcasing are coated with guideand roll surfaces of a material resistant torolling friction.

5. A reversible planetary piston pump as claimed in claim l, in whichgroove-shaped recesses are provided at the inlet'and outlet open# ingsand the impeller carries an elastic coating having sealing edges thereonsaid sealing edges being so disposed that when the respective pumppistonris in its inner position the respective edges are in a sealingposition in the recesses, the said recesses being deeper than the heightof said sealing edges, so that a space for'liquid is obtained in orderto moderate the motions of the pump elements.

l 6. 'A reversible planetary piston pump, as claimed in claim 1, inwhich the extension of the slots in the walls of the pump casing in theplane through the piston axes equals approximately the Sum of thediameter of said shaft plus the radius of the circles about which thecenters of the plstons oscillate, the central line of said slotscoinciding with the transversal plane through the center of the pumpcasing.V

7. A reversible planetary piston pump, as

claimed in claim 1,7m which groove-shaped recesses are provided at theinlet and outlet openings and the impeller carries an elastic coatinghaving sealing edges thereon, said sealing edges being adapted to restin a sealing position in said recesses when the respective pump pistonis in its inner position.

GUSTAV RUDOLF' LIN DBERG.

